One-way valves for controlling flow in fluid systems are relatively common. Valves having one condition permitting flow in one direction within a system while, in a second condition, remaining opened or closed are less common.
For example, U.S. Pat. No. 3,308,846 discloses a pressure relief valve which is closed by the combined forces of an energized solenoid and a spring element. When a predetermined system pressure is sensed the solenoid is de-energized. The system pressure force overcomes the spring element force so the valve opens to vent the system to the atmosphere and relieve the pressure. Sensing a reduced system pressure re-energizes the solenoid, reclosing the valve.
U.S. Pat. No. 5,056,556 discloses a solenoid and single spring associated with a complex, multipart valving arrangement. The '556 patent valve is described as functioning as a relief valve as well as an on-off valve.
U.S. Pat. No. 4,631,923 discloses a valve arrangement in which a valving member is acted upon by a compression spring to close the valve and alternatively, when the solenoid is energized, by a tension spring to enable flow.
Where solenoid operated valves have been used to control air flow in out-of-doors settings, for example in automotive vehicles, low ambient temperatures have caused operational problems. For instance it has not been uncommon for such valves to be frozen in one operating condition. A typical case is where atmospheric moisture condenses and freezes while adhered to a valving member and a seat with which the valving member is engaged. Such a valve is frequently "stuck" in its closed condition until melting occurs.
The present invention provides a new and improved fluid flow control valve assembly having one operating condition wherein a valving member enables one-way system fluid flow and a second operating condition in which the valve is closed to system flow and wherein the valve assembly is so constructed and arranged that the valving member is shocked to minimize the likelihood of the valving member being stuck closed when the valve assembly is in the first operating condition.